Degradation processes of organic materials are typically based on oxidative degradation and may lead to discoloration (yellowing) or change of mechanical properties such as brittleness or loss of strength. Another consequence of oxidative degradation can be release of undesired low molecular weight compounds which may involve unpleasant odour or reduced aesthetics. Oxidative degradation typically limits the applicability of otherwise suitable materials or compositions. Particularly within the materials industry there is a strong need for materials that does not deteriorate significantly during their lifetime. A colour change of a product during the first few year of utilization is usually not acceptable to the customer. Examples of such products are coatings used for boats and high quality furniture.
Light protective additives are added to organic compounds to inhibit their degradation under influence of light. An extensive overview of light protective additives for polymer materials are provided by Hans Zweifel (ed.), “Plastic additives handbook”, Hanser, München, 2000. As light protective additives are typically used additives with UV absorbing properties (Hans Zweifel (ed.), “Plastic additives handbook”).
UV absorbers that are used in polymer materials should fulfil three important criteria. Firstly the UV absorber should have a sufficiently good absorption in the wavelength range 300-400 nm. Secondly the UV absorber should have a sufficient stability in the relevant application to avoid that its UV absorption decreases over time. Thirdly the UV absorber should be easy to mix into the material or composition in which it is to be used.
Examples of UV absorbers with good absorption in the 300-400 nm wavelength range having good stability during time of use are chemical compounds based on triphenyl triazine which is described e.g. in WO 97/36880, EP 434 608, EP 520, 938, U.S. Pat. No. 4,619,956, EP 483,488, EP 500,496, EP 502,816, and EP 506,615. Other examples of UV absorbers with good absorption in the wavelength range 300-400 nm which also have good stability under time of use are chemical compounds based on benzo triazoles which are described e.g. in U.S. Pat. No. 5,977,219, U.S. Pat. No. 5,607,987, and U.S. Pat. No. 5,516,914. To be able to mix such UV absorbers into polymers and polymer forming compositions such as thermoplastics, thermosetting plastics and coating forming compositions usually a step of formulation is required.
One way of avoiding such a formulation step is to chemically bond UV absorbing chemical compounds to organic polymer molecules with a branched structure. Such polymers can due to their branched structure easily be combined with all kinds of polymers and particularly with thermosetting plastics and coating forming compositions.
In addition to pure polymer materials there has also been developed products based on materials that may be described as hybrids between inorganic and organic materials, which means that these materials are macro molecules that may have an inorganic core and organic branches.
Organic polymer molecules with branched structures have an enormous economical growth potential, particularly as components in new materials. So-called dendrimers are important examples of such polymer molecules with a perfectly branched structure as well as hyperbranched polymers with statistically progressive branching. Both dendrimers and hyperbranched polymers are denoted dendritic polymers. Dendritic (from Greec: “dendron”=tree) characterizes the principle of a progressive branching that is more or less perfect (G. R. Newkome, C. N. Moorefield, F. Vögtle, “Dendrimers and Dendrons: Concepts, Syntheses, Applications”, Wiley-VCH, Weinheim, (2001)). Formula 1 illustrates the principle difference between linear polymers and dendritic polymers (hyperbranched polymers and dendrimers).

Dendritic polymers are particularly interesting because the T units may carry functional groups and the density of available functional groups per weight or volume unit of the polymer is much higher than what is the case for linear polymers. Functional T groups may be used to impart a function in a material, like an antioxidant, an UV absorber, or a radical scavenger as described in WO publication No. 02092668.
Alternatively the T groups may be used as very efficient cross-linkers of organic materials like epoxy resins or polyurethanes or as cross-linkers for thermoplastics. Due to the high degree of cross-linking between dendritic polymers and such organic compounds the dendritic polymers are superior cross-linkers compared to conventional cross-linkers like polyamines, polyalcohols, or multifunctional acrylates. Higher degree of cross-linking of an organic material like a cross-linked thermoplastic improves properties such as chemical resistance, weather resistance and wears resistance and makes the material useful for applications at higher temperature. (Hans Zweifel (ed.), Plastics Additives Handbook, Carl Hanser Verlag, München, (2001), 725-811). The T groups may also be used to organize the dendritic polymers in a network. As component in a material the dendritic polymer thus may induce improved barrier properties. Alternatively such dendritic polymers may be used as a binder or as a component in a thermoset plastic.
Dendrimers are usually manufactured in relatively complicated and expensive synthesis comprising several steps. The process conditions must be maintained very accurately in order to achieve a perfect progressive branch structure. Their industrial applications are therefore limited.
A general way of manufacture of hyper branched polymers was early described by Flory (P. J. Flory, Principles of Polymer Chemistry, Cornell University, (1953)). The polymerization of an AB2 monomer where A may react with B but where the reactions between A and A and between B and B are precluded, leads to a hyperbranched polymer.
Another way of manufacturing hyperbranched polymers involves the utilization of a reactive monomer that also carries an initiator, a so-called “inimer”. One example is the base catalyzed reaction between the inimer glycidol and the germ trimethylol propane as illustrated by Formula 2.

Hyperbranched polymers made in this way have properties that are quite similar to corresponding dendrimers (A. Sunder, R. Hanselmann, H. Frey, R. Mühlhaupt; Macromolecules, (1998), 32, 4240). This implies a much lower viscosity than that of linear polymers with a comparable number of free available HO-groups. A characteristic feature in the manufacturing process is that the inimer glycidol must be added very slowly to the germ and in a very thin dilution. Thus, the cost-efficiency of the process is severely reduced which is why the utility of hyperbranched polymers in industrial applications is quite limited.
It is previously known to perform certain modifications of the T groups of hyperbranched polymers. J.-P. Majoral, A.-M. Caminade and R. Kraemer, Anales de Quimica Int Ed., (1997), 93, 415-421 describe the functionalizing of dendrimers containing phosphorus. The functionalizing of the T groups can be made with identical/similar chemical groups or with different chemical groups.
FR 2761691 discusses dendrimers with functional groups at the surface that are modified through a reaction with cyclic thio esters. The reaction leads to a dendrimer surface with thiol groups that are attached to the dendrimer by amide or amine bondings. The products are useful as antioxidants. The dendrimers described are of the type polyamidoamine dendrimers (PAMAM dendrimers). PAMAM dendrimers contain tertiary amines that comparatively easy may be degraded after conversion to quaternary ammonium salts or aminoxides (A. W. Hofmann, Justus Liebigs Ann. Chem. (1851), 78, 253-286; A. C. Cope, E. R. Trumbull, Org. React. (1960), 11, 317-493; A. C. Cope, T. T. Foster, p. H. Towle, J. Am. Chem. Soc. (1949), 71, 3929-3935). Quaternary ammonium salts or aminoxides from amine based dendrimers can be formed when additives of amine based dendrimers are incorporated/compounded into thermoplastics with subsequent processing of the thermoplastics (e.g. film blowing, extrusion, casting). Such a degradation on one hand leads to a partial deterioration of the dendrimer core and on the other hand to formation of degradation products which may leak out and thereby reduce the surface quality of the polymer product. In addition tertiary amines may during processing of the thermoplastic form free radicals by decomposition of hydro peroxides (A. V. Tobolsky, R. B. Mesrobian, Organic Peroxides, (1954), Interscience Publishers, New York, p. 104-106). Dendrimers and hyperbranched polymers that contain tertiary amines thereby may induce an unintended degradation of thermoplastics during their processing, storage or use.
WO 01/48057 discusses multifunctional stabilizers against thermal oxidative degradation based on a core structure containing tertiary amines. As mentioned above, this may lead to an unintended degradation of the core structure during processing, storage or use of (the) thermoplastics. The molar weight of a typical stabilizer manufactured in accordance with WO 01/48057 is 1246 g/mole.
WO 97/19987 discusses combinations of polymer additives and modified dendrimers that are useful in polymer materials. In the exemplification of WO 97/199987 the dendrimers are based on polypropylene imine (PPI) of 3rd, 4th and 5th generation thereby including 16, 32, and 64 terminal amine groups. The core structure contains tertiary amines which may lead to an unintended degradation of the core structure during processing, storage or use of thermoplastics. The modification of the PPI dendrimer with a fatty acid to form a multifunctional fatty acid amide may bee conducted by means of heating in a suitable solvent. The tertiary amine groups in the core structure of the dendrimer and primary amine groups at the dendrimer surface may in presence of oxygen contribute to partial degradation of the dendrimer structure. As explained above free radicals may be formed by decomposition of hydro peroxides. Such a partial degradation is indicated by a faint brown or yellow colour of the modified PPI dendrimer, like in examples 1, XI, and XII in WO 97/19987. Typical molecule weights for modified PPI dendrimers in WO 97/19987 are in the range 10 000 to 40 000 g/mole. In WO 02/092668 permanent or surface activated hyperbranched or dendritic stabilizers comprising at least one additive group and a hyperbranched or dendritic core are discussed. In the exemplification of WO 02/092668 only dendritic cores based on 2,2-bis-(hydroxymethyl)-propionic acid is used. The dendritic core and the bonding to the additive group thereby are mainly based on ester bondings, which make the stabilizer sensitive to hydrolysis. In addition the exemplification of WO 02/092668 shows that the molecules of the prepared stabilizers as determined by gel permeation chromatography is between 1000 and 1500 grams/mole. When the stabilizer shall function as an UV absorber the additive group which chemically bonds to a hyperbranched or dendritic core, is always as such approximately as good an UV absorber as the manufactured stabilizer. The way in which the additive group bonds to a hyperbranched or dendritic core has little or no influence on the UV absorbing properties of the manufactured stabilizer.
One type of particulate polymers with properties corresponding to the properties of hyperbranched polymers comprises an inorganic SixO(1.5)x-core with one T group per Si atom and is known as POSS (polyhedral oligosilesquioxanes). The most common compound of this class is a POSS with x=8 and substantially cubic structure (C. Sanchez, G. J. de A. A. Soler-Illia, F. Ribot, T. Lalot, C. R. Mayer, V. Cabuil; Chem. Mater., (2001), 13, 3066). The manufacture of POSS is expensive (M. C. Gravel, C. Zhang, M. Dinderman, R. M. Laine; Appl. Organometal. Chem., (1999), 13, 329-336 and WO 01/10871) and their industrial applicability is therefore limited.
Another type of particulate polymers with properties corresponding to the properties of hyper-branched polymers consists of an inorganic SixO(1.5)x core that carries one T group per Si atom and may be manufactured in a sol-gel process through controlled hydrolysis and condensation of a silane with a structure:X—B—Si(—Y)3 where Y is chosen among hydrolysable residues and X—B basically corresponds to the T group. The process is described e.g. in WO publication No. 0208343. Sol-gel processes may be cost efficient so that they may be conducted in industrial scale from favourable raw materials and under mild conditions, i.e. without use of high pressures or high temperatures and without particular precautions like extreme dilution or the like. Thus particulate polymers with properties corresponding to properties of hyperbranched polymers manufactured by sol gel processes are industrially applicable in many areas. Many examples of utilization of sol gel products in polymer products are known (DE 199 33 098, EP 666 290). Normally the main focus is placed upon the inorganic SixO(1.5)x core with a size in the nanometre range and thereby upon the sol-gel product as inorganic nano particle, cf. DE 199 33 098 and EP 486 469. The inorganic residues X—B are typically used to anchor the sol gel products in an organic matrix, cf. EP 486 469.
The sol gel process involving hydrolysis and condensation of a silane in which the X—B group contains one or more amide groups is particularly simple because no external catalyst is needed and because the process may be conducted at ambient temperature or under moderate heating. One example is controlled hydrolysis and condensation of γ-aminopropyl trialkoxysilane as described in applicant's own patent application, WO publication No. 0208343. Controlled hydrolysis and condensation of silanes in which the X—B group contains one or more amide groups typically leads to a sol in which the resulting particulate polymer product has an organic/inorganic structure (hybrid polymer) that is comparable with a hyperbranched polymer product with a number of more or less free amine groups in the T groups. Such organic/inorganic hybrid polymers exhibits a large number of functional T groups compared to their weight and/or volume. At the same time its compact structure compared to the structure of linear polymers ensures desirable properties like low viscosity and good admixing properties with thermoset plastics and thermoplastics. An example of an organic/inorganic hybrid polymer with properties corresponding to a hyperbranched polymer is shown by Formula 3:

Organic/inorganic hybrid polymers with properties corresponding to those of hyperbranched polymers find use e.g. as additives for thermoset plastics, in lacquers and other types of coatings for surface protection. Used in appropriate amount and particle size such hybrid polymers can contribute to a substantial improvement of the properties of the plastic material, lacquer or other type of product in question, hereunder particularly increased wear resistance/scratch resistance and/or weather resistance.
Prior art technology in the area of sol-gel processes can coarsely be divided into four main categories as explained in further detail below with reference to some examples or publications.
A first category concerns modification of non-hydrolyzed amine containing silanes (DE 2023968, WO 03/029361, EP 0253770, EP 666290) typically with bifunctional epoxy compounds (like e.g. JP 2001192485), and use thereof n coatings. Hydrolysis and condensation are thereafter conducted in some embodiments prior to the addition to the thermoplastics or coating in question. In general this method involves an undefined molecular size distribution with a high number of large molecules. This means i.a. that subsequent hydrolysis is not easily conducted since water does not easily reach all sites on the large molecules. A low degree of hydrolysis implies lower scratch resistance and weather resistance for the product. A further disadvantage is that water used for hydrolysis in presence of the organic parts of the molecules may react in an undesired manner with active groups on the organic parts. The utilization of a non-hydrolyzed alkoxy silane compound in a thermoplastic or thermoset plastic material leads to formation of alcohols such as ethanol and/or methanol during the subsequent sow hydrolysis of the silane compound, i.e. after that the thermoplastic or thermoset plastic has been exposed to moisture. This can lead to weakened mechanical properties for the thermoplastic or coating. In addition the formation of alcohols such as ethanol and/or methanol may cause migration of additives and/or degradation to the surface of a thermoplastic material or coating which can significantly reduce the surface quality.
Another category of prior art methods concerns modification of nitrogen containing sol-gel products through chemical reactions where the amine groups are not directly involved (S. kar, P. Joly, M. Granier, O. Melnyk, J.-O. Durand, Eur. J. Org. Chem.; (2003), 4132-4139) or are not significant (U.S. Pat. No. 5,744,243). The latter patent concerns a coating composition which is obtained by combination of a) acid catalyzed hydrolysis and condensation of silane and monomer, b) a polymerized solution of organic polymer comprising functions which are compatible with the silane monomer. The coating is used for light reflection.
A third category concerns surface modification solely of SiO2 particles, i.e. silica particles which may or may not be manufactured by a sol-gel process. A (non-hydrolyzed) silane is typically used to modify these particles, the silanes thereby forming branches on the particles. This type of modification does not involve amine groups as reactive sites for the modification. The patent application No. 9603174-5 describes aqueous dispersions of silica particles in different polymers, used i.a. to increase hardness.
WO publications Nos. 9407948 and 00/22039 concern this known technology in which a surface modification of the oxide particles is conducted trough silanization. In some cases the oxide particles can be made of hydrolysed silane. These particles are used as fillers and for modification of polymers and foils. A disadvantage of products including such particles is that they are not fusible after curing and their use as hyperbranched polymers is therefore limited. A disadvantage of this technology is that each silane has several functional groups which do not necessarily bind to one and the same particle. If or when a silane binds to two different particles it contributes to an undesired agglomeration of particles. This may take place at once or over time which means that the system is unstable. It should furthermore be noted that due to the size of the silanes only a limited number of functions can be attached to each particle, i.e. the degree of hyperbranching is comparatively low. EP 0786499 describes a composition that is curable with moisture and comprises a) a multifunctional acrylate, b) at least one alkoxy-functional organometallic component (TEOS) or hydroxylate, and c) at least one trialkoxyaminosilane.
A fourth category of prior art technology is constituted by sol-gel processes based on hydrolysed silane and involving a modification with an organic monomer, prepolymer or polymer.
EP 486 469 describes an organic/inorganic hybrid polymer obtained by polymerizing an organic monomer in presence of a wholly or partially hydrolysed silane based sol. A typical example from EP 486 469 is polymerizing of methylmetacrylate in presence of a sol made using methacryl oxypropyltrimethoxysilane. The resulting composition is intended to be used for wear resistant coatings.
U.S. Pat. No. 5,674,941 teaches a coating forming composition comprising hydrolysate/condensate of a) en epoxide containing silane, b) an organic aminofunctional silane, c) a copolymer of two components chosen among an acrylate monomer, an epoxy monomer, an organosilane and/or a terpolymere of said three components, and d) a curing catalyst, e) a multifunctional acrylate, f) an initiator for radical polymerisation. This composition is very complex and a chemical conversion of amine groups to form a polybranched organic/inorganic hybrid polymer is not described.
U.S. Pat. No. 5,096,942 concerns a process in which a polymer is first made based on a hydrolysed silane, a so-called inorganic core, which is attached to a polymer chain like e.g. polystyrene. The hydrolysis of the silane is conducted so that the condensation between Si—OH groups is actually prevented. A hydrolysed metal oxide or silane is thereafter added to the hydrolysed silane resulting in an organic/inorganic hybrid polymer with properties corresponding to the properties of a hyperbranched polymer with a molecular weight in the range 1000-100000 g/mol. The silane is not nitrogen containing and no intended chemical conversion of free amine groups in the sol is mentioned in U.S. Pat. No. 5,096,942.
U.S. Pat. No. 5,110,863 teaches the manufacture of a sol containing an organosilane (with imidazol) and metal oxide which is hydrolysed and can produce an independent coating.
WO 2005 100450 concerns a method for the manufacture of different types of polybranched inorganic/organic hybrid polymers. The method is based on a chemical reaction between one amine group n a polybranched inorganic/organic hybrid polymer and a suitable monofunctional chemical compound. The reaction of two or more amine groups in a polybranched inorganic/organic hybrid polymer with a multifunctional chemical compound leads to loss of the particulate properties of the polybranched inorganic/organic hybrid polymer. Manufacture of polybranched inorganic/organic hybrid polymers with UV absorbing properties is not discussed.
Silicone based polymers and oligomers with chemical bonds to UV absorbing groups are described in JP 07267842, US 2005249690, JP 2006225358 and EP 138590.
EP 275719, EP 955288, US 2005180933 and WO 2005025491 all describe UV absorbing materials made by chemical conversion of amines and polymer amine compounds with UV absorbing chemical compounds. The UV absorption is usually strong at wavelengths<350 nm and usually strong in the wavelength range 350400 nm. These UV absorbing materials thus have a limited use as light protective material for the entire wavelength range 300-400 nm.
UV absorbers with low tendency of leakage and so-called “blooming” from materials and compositions in which they are used, are described in US 2005023268, DE 19649191, JP 10212469, and EP 744632. Leakage and blooming are reduced by improvement of the fat solubility of the UV absorber or by chemically to bind the UV absorber to a material or component in a material composition.
UV absorbers to be used in aqueous formulations are described in DE 20 2006 007 976 U1 and FR 030 4650.